Question

va rog ajutatima repede

Answer 1

a)
f(x)=2x^3-6x+7<=>f(1)=2*1^3-6*1+7=2-6+7=3
f'(x)=(2x^3-6x+7)'
f'(x)=(2x^3)'-(6x)'+7'
f'(x)=6x^2-6<=>f'(1)=6*1^2-6=6-6=0
f"(x)=(6x^2-6)'
f"(x)=(6x^2)'-6'
f"(x)=12x<=>f"(1)=12*1=12
f(1)+f'(1)+f"(1)=3+0+12=15

b)f'(x)=0<=>6x^2-6=0<=>6x^2=6<=>x^2=6/6<=>x1=1;x2=-1(punctele de extrem)

Se face tabel de monotonie

|x    |-infinit    -1       1          +infinit
|f(x) |+++++++0------0+++++++++

la c  nu stiu